Variable-load brake



Feb. 24, 1931. I u. A. WHITAKER 1,793,573

,ymmsun LOAD BRAKE Filed Oct. 12, v1929 70 INVENTOR v UNCAS A Wl-RTAKER70' I 72 MW ATTOR EY Patented Feb. 24, 1931 QFFICE;

UncAs A. WHITAKER, oncan'roiv, OHIO, ASSIGNOR TO 'rnn-wnsrrnenousn AIRBRAKE COMPANY, or wrLI-aannrne, PENNSYLVANIA, A.ooaronerron,oF-rmvnsYLvANIA VARIABLE-LOAD BRAKE Application filedOctober 12, 1929. Serial No. 399;;55.

This invention relates to fluid pressure brakes for vehicles, and moreparticularly to a brake apparatus 'adapted to vary the braking poweraccording to the load on the car. v

I The principal ob ect of my'inven'tion' is to 'provice an improvedvehicle variable load brake apparatus having means operative uponopening a door of the vehicle for varying the maximum pressure of fluidobtainable, 1n the brake cylinder accordlng tothe load carried i VAnother object of my invention is to provide an improved vehiclevariable load'brake apparatus having means adjustable accord- 15 ing tothe load on the vehicle and operative upon the opening of the veh cledoor for controlling the maximum pressure of fluid .ob-

tainable in the brake cylinder.

A further object of my invention is to provide an improved vehiclevariable load brake I apparatus having pressure sensitive meansinterposed between thebody and atruck offthe vehicle adjustableaccording to the load on the car and o-peratlve upon the opening of adoor of the vehicle for controlling the maximum pressure or fluidobtainable in the brake cylinder. r H

Other objects and advantages will appear in the following more detaileddescription of U the invention. r

' In the accompanying drawing, Fig 1 is a diagrammatic view, mainly insection, of a variable load brake apparatus embodying my 1 invention;Fig. 2 is a diagrammatic view of a portion of the. apparatusillustratinga modification of the invention.

In the drawing, the reference character 1 indicates a vehicle body whichis supported on the usual vehicle truck not shown, 2 the upper member orcover plate. of the truck bolster, which constitutes a part of thevehicle truck, 3 a-brake cylinder pressure limiting V valve device, atan adjusting piston device, .5 control valve device, 6 a main reservoir,7 a brake cylinder, 8 an application pipe, which inthe presentembodiment is a straight air pipe, and 9 amagnet valve device.

The brake cylinder pressure limiting valve device may comprise a casinghaving a flexible diaphragm 10'mounted therein adapted to control theoperation of a valve 11 contained in a valve chamber 12. Also containedinth'e chamber 12 is a spring 13 which isin'terposed between a cap nutll, having screw threaded connection with the. casing, and the 2 upperside of thevalve 11, which spring tends to seat the valve 11. f l

The chamber 1 5 at one side of the flexible diaphragm. 10 is vconstantly connected :to the brake cylinder 7-1through a passage andpipe 16; Contained ina chamber 17 at the other which is subject to thepressure of an adjustable spring- 19, said spring being adjusted'bymeans of a plunger- 20 which is slidably mounted in the lower endportion of the casing, and which-is in engagement with the lowerendotthe spring 19.

Having screw threaded connectionwith the plunger body and extendingtherebelow is a bolt 21, andhead 22of which, is adapted to be engaged byan arm 28 whichis secured to a shaft 24, rotatably mountedgin a bracket25, which may beintegral with the casing of the vbrake cylinder pressurelimiting valve device 3. '7

Also secured to the shaft 24, is an arm 26 which, at its free end, isprovided with a toothed segment '27;

Located above the arm 26, is a pawl 28 which, in the presentembodimentof'the invention, is in the form of a bell crank having arms29 and 30 and which is mounted to rock on a projection 31 preferablyintegral with the casing of the limiting valve device 3. The arm29 isprovided with teeth adapted to engage the teeth of the segment 27 tolock the arm 26 in an adjusted position, as will be hereinafter morefully described. 7

For the purpose of operating the pawl 28 so as to move the teeth on thearm 29 into nected with the arm 30 of the pawl through the-medium of apin 36. Surrounding the piston stem 35, and interposed between and sideof the diaphragm 'l0 is a follower 18;,

engaging the piston 34: and a bracket 37,

which may be integral with the casing, is spring 88, the pressure 01'which tends to maintain the piston in its normal right hand position andthe pawl in locking engagement with the segment27 as shown in Fig. 1.

The adjusting piston device 42' may comprise a casing containing apiston 38 having astem 39 which projects through the end of the casing:and whiclnat its outerend, "isprovided with a #roller 40' adapted toerr- ,ing secured to the vehicle body '1 and the part 45 beingsecured.tothetruckbolster 2 or to any other desired party of the truck.

Mountedin the part His a flexible diaphragm 46, the underside of which*is engagedby atollower 4:7,subject to thepressure of a spring 48through the medium of aspring seat 49, the lower. end of the springseating on a spring-seat 50 secured to'the upper end ofgthe part '45-Engagingthe uppersideot the flexiblediaphragm e6, is

a plunger 51 which is subject to the pressure of a coil spring 82,.whichplunger is loosely connected with a dischargevalve 52 contained in avalve chamber-53 constantly connected with a diaphragm chamber 54 at oneside of the diaphragm 46 through a passage 4 Thejloose connectionbetween the stem of the valve 52 and the plunger 5lis'made by passing apin 56 throughtheplun'ger and through a slot 57 formed in the stem andanchoring the ends of the pin to the plunger. Interposed between thelower-end of the valve stem and the plunger, is a spring 58-whichtendsto maintain the valve 52 seated and the valve stem, at-thelower endof the slot 57,in engagement with the pin 56, so that when the plunger'51 move-s downwardly, such movement will-.beimmedi-ately transmitted-tothe valve stem and cause the-valve 52 tobennseatedt It will be notedthat by the use 0t this loose connection, theplunger 51 is permitted tomove upwardly relative to the valve stemaso that'when the valve 52 isseated, upward movement of the diaphragm, due to track conditions,cannot be directly transmitted to the valve, thus-guarding the valve andits seat against damage.

The magnet valve device 9 may comprise a'magnet 59 which -is adapted tocontrol the operation of valves 60 and 61contained in chamhers 62 and 63respectively. The valve chamber 63 is connected to the a;- mospherethrough a passage 64 and the valve chamber 62 is constantly connectedwith a .opened.

l atmosphere.

volume reservoir 65 through a passage 66,

ton chamber 7 2 at one'sideot' the piston 38 is also connected to thechamber 69 through a branch pipe 73, past a ball check valve 7 4 .and apassage 75, the passages 7 3 and.

in advance of the ball check valve 74 being also connected through arestricted passage 76 I he coil of the magnet 59 iscoimected in acircuitincluding a source ofcurrent T'? and including a switch78which iscontrolled by the opening and-closing of a door .79 of the vehicle,-sothat when the door is open, the magnet circuit will be closed and whenthe door 1s closed, the clrcuit' will be In operation, when the car isrunning along the road, with the car door 7 9 in closed position, asshown in full lines, the magnet circuit will be-open and. the magnet 59will be deenergizcd. YVith' the magnet valve 59 deenergized, thepressureof. a spring 80 contained in the valve chamber .62 will maintain thevalve 60 seated and the valve 61 unseated.

With the valve 60 seated, flow of fluid under pressure'trom the mainreservoir 6- and volumereservoir65-to the chamber 69 is closed off,and-with the valve 61 unseated, .the pi-ston chambers 71 and 72 of thepawl operating piston dev ce and admstmg piston device, respectively,valve chamber 53' and diaphragm ClIZIIHlJBFfii are connected to the Withthese chambers. thus connected to the atmosphere, and the-vehicle empty,the several parts of the mechanism will be (in their normalpositions-asshown .in the drawing, so thatthe brake cylinder 7 will be connected tothe atmosphere byway V of pipe and passage'16, diaphragm chamber 15, inthe brake cylinder pressure" limiting valve device3,'-past the .unseatedvalve 11, through valve chamber 12 and a passage and pipe 81 and pipe 8,and through the usual brake valve device, (not shown),

To bring the vehicle to a stop, it is the usual practice to firstoperate'the brake valve device to applicationposition'to effect a full 7service application of the brakes and then as the speed of the vehicleis reduced, operate the brake valve device to reduce the pressure offluid in the brake cylinder and then as the vehicle comes. to. a stop,operate the brake valve device to lap position tomaintain suiti-1,793,573 A n a cient pressure in the brake cylinder to hold thebrakesappliedqi' 7 In effecting an applicationot'ithe brakes,

fluid under pressure is supplied to the brake cylinder by way of pipe 8,pipe and passage 81, valve chamber 12 past the unseated valve 11,diaphragm chamber and passage and pipe 16. N0w,when thecar comes to astop,

and one of the doors moved to'open position, the magnet circuit will beclosed, and the 'magnet 59 energized lVith the magnet 59 thus energized,the valve 61 will be seated and 7 With the valve 'u'n'seated, fiuidunderpressure flows to the chamber 69 of the magnet valve device fromthe valve 60 unseated.

the volume reservoir by way of passage 66, valve chamber 62 and past theunseated valve 60. From the chamber 69 fluid under-pressure is suppliedto the valve chamber 53 and diaphragmchamber 54 ofthe control valvedevice 5, by way of passage and pipe and passage '55, and to the pistonchamber 71 of the awl o eratin )iston device 33 b Y wa a ll mainreservoir'6 through the choke passa e of passage 70.

- From the passage "7 0, fluid under pressure flows to the pistonchamber 72 of the adjust ing piston device 4 by way of branch passage 73'past the ball check valve 7 4 and passage 75.

Now, with the vehicle empty, the pressure of fluid supplied to thediaphragm chamber 54, inthe control valve device 5, will move downwardlyagainst the pressure of the spring 48, and permitthe pressure of thespring 82 to move the plunger 51 downwardly and unseat the valve 52. r I

With the valve 52 thus unseated, further build up of pressure in thepiston chambers 71 and 7 2 will be prevented, by the venting of thefiuidunder pressure, supplied from the 68, volume reservoir 65, passage66 and through the magnet, valve device 9, to the atmosphere past theunseated valve 52 and through a passage 83. 1

\Vhen fluid under pressure is supplied to the piston chamber 72, thepiston .38 moves downwardly, and when fluid under'pre'ssurc is suppliedto the piston chamber 71, the piston 34 operates against the pressure ofthe spring 88, to rotate the pawl 28 about the lug 31, thus moving theteeth of the arm 29 out of locking engagement with the teeth of thesegment 27. The piston 38 will move downwardly against the'pressure ofthe spring 43 until the'rollermounted on the stem 36 "thereof engagesthe upper. surface of thev arm 41, at which time, the valvef52 of theconm valve device will be unseated, so that there willbe no furtherbuild upof pressure in the piston'chan'iber 7 2 andthedownward movementof the piston 38 will come to astop without having operated the lever41.

Now, ifthere has been no load added-to the vehicle, and the door 7 9 ismoved to its closed positiomthe electric circuit through themagnet 59will be open and the magnet denergized. When the magnet is thusdeenergize'd,

the pressure of the spring contained in the valve chamber 62 of themagnet valve "device operates the valve 60 to its seated position,

and the valve 161 to its unseated position, With the valve 61 unseated,the pistoncham- 1 her 71 will be vented to the atmosphere by Way ofpassage 70, chamber 69 in the magnet valve device, past'the unseated'valve 61,

through chamber 63, and passage 64. Inthe same manner, fluid underpressure from the diaphragm chamber 54 Of'tllB control valve device 5will be vented to the atmosphere.- Upon thus venting. the chamber71',"the pres sure of the spring 88 causesthe pawl 28 to operate insuchamanner that the teethof the arm 29 thereof will lockingly engagethe teeth of the segment 27 on the arm 26. N,

Upon the venting of the chamber 54 of the control valve device, the 7pressure of the spring 48 will flex the diaphragm 46 upwardly, causingthe plunger 51 to be operated'upwardly against the pressure of thespring 82,

and as this plunger is so moved, the pressure of a spring 58'will seatthe valve 52.

The pressure of fluid is vented from the piston'chamber 72 at-arestricted rate through the passage 75, restricted passage 76, passage 73, and thence to the atmosphere through pas sage 70 and the magnet valvedevice 9. It will here be notedthat the piston chamber 71 isivented tothe atmosphere at an unrestricted rate, while the piston chamber 72 islvented t0 the atmosphere at a restricted rate, and'this is for thepurpose ofinsuring the teeth of the arm 29 being in looking engagementwith the teeth of the segment 27 before the piston 38 is operated out ofengagement with the arm 41, so that the pressure of the spring 19 cannotchange the adjustment of the lever.

When, in effecting a full service application of the brakes,--the brakecylinder pressure present in the diaphragm chamber 15 in the pressurelimiting valve device. 3, acting on one side of the flexible diaphragm10,

is sufficient to overcome the pressure of the spring 19, acting on theother side, sa d diaphragm will flex downwardly permitting the pressureof the spring 13 to seat the'valve 11 to close off the further supply offluid under pressure to thebrake cylinder and thus limit the brakecylinder pressure, The imi-PYGSSUIQ Of'flUJCllII the diaphragm chamber.5 1, as well as in'the piston chamber. 72 of the 19 deterniinesithemaximum brake 1 cylinder [pressure obtainableion any empty vehicle.

. If, when the door is open, aload is added to thevehicle', the vehiclebody 1 'willlmove .-downwardly relative to the truck, and inso(101115151 compresses the I spring 48, thus in:

The .diaphragm now operates upwardly, causlngfthevalve 52 to be-seated,'so-that the adjusting piston. device 4,-is increased. As

: thepressure ot'fluidinthe chamber 72 is ithus increasedfthe'piston 38,stem-39 and v -rolleriO "will. be operated downwardly against" thepressure of the spring 43, caus- 111mg.. theJarm 41'to be operated torotate the :yshafti'2t1na clockwisedirectiom As the shaft is thusrotated, the arm23 secured "thereto'will be. moved upwardly, operating.i the plunger upwardly, compressing the .-spr1ng 19, thus ncreasing thepressure of the spring acting on the-diaphragm 10.

i 'phragm' chamber 54 in the control valve de-- Now, when the pressureof fluid in the diavice slightly. exceeds the adjusted pressure otthespring 48-,the diaphragm 4:6 is flexed downwardly permitting thedischarge valve 52 to-be againLunseat'ed, thus preventing the furtherbulld up of pressure in the ad usting piston chamber'72 and in thecontrol valve ==diaphragm chambered. Since thefurther build up inpressure: of fluid in the piston chamber72 is not permitted, thepressure of the spring 43 causes the downward movement of the piston '38and the adjustment of the pressure regulating spring 19 to cease.

Now, when the vehicle door-79 is closed, the magnet circuit is opened,causing the deenergization ofthe magnet 59. Upon the -deenergization ofthe magnet, the pressure of the spring 80 operates the pressure supplyvalve to its seatedposition, closing off the further supply of fluid tothe piston chamber 71- in the pawl operating pistondevice 33. theadjusting piston chamber 72,

and to the diaphragm chamber 54 in the con-' trol valve device, andfurther operates the discharge valve 61 to its unseated position,

venting these chambers 71, 72'and 54; to the .atmosphere by way ofpassage70, chamber 69 in the'magnet valve device, past the unseatedvalve 61, through valve chamber 63 and passage 64.

Since the piston'chamber 71 is vented to the atmosphere at a much fasterrate than the pressure of fluid in the adjusting piston chamber'72 canbe vented by way of the restricted passage 76, the pressure of thespring 88 willcause the pawl operating piston 34 to: move toits righthand position, rocking J tance that-the teeth on the pawl arm 29thepawl'28 on the lug 81 a suflicient disengage the teeth of the segment27, of the device to release position.

spring j the foregoing description .it willrbe arm: 26 secured to 'the.'24,-.wbet'orehthe lViththe teeth of the pawl'ar1n-29. thus inengagementwith=the teetlrof the segment 1 27, the arm 26 will be locked inadjusted posie :tion against the downward pressureiof' the creaslng. itspressure on the diaphragm 46.:

spring 19 actingthrough the plunge1i-20, bolt 21,arm 23and shaft hthusmaintainingthespringflt) adjusted.

. The brakes may now. be released inpthe usual manner by operating thebrake :valve If afull serviceiapplication"of the brakes is effectedafter the apparatus has thusbeen adjusted, the brake cylinder pressurewhich it is possible to obtain will be; greater'than that which canbeobtained whenn'the" apparatus is adjusted foran empty vehicle due to theincrease in-the 'pressureqof the From 7 seen that,'since the pawl '28 isoperatedout of locking engagement with the arm 26 each time the door isopened, the apparatus'will be automaticallyadjusted asthe load on'thevehicle is being increased and; decreased.

.Vhen the vehicledoor'? 9 is open and the vehicle fully loaded, thecontrol valve "device will be so adjusted, by thedow-nwardmovement ofthe vehicle body relativeto the truck,

that the pressure-of fluid will build up sufficiently in the adjustingpistonchamber 72 to cause the piston 38- to move outwardly and cometo astop against an'annular shoulder 85 tormedinteriorly of the casing ofthe adjusting piston device 4, When the piston engages the shoulder 85,the-maximum'adjustment of the spring 19 of the brake cylinder pressurelimitingdev-ice will have been made so that in effecting a serviceapplication of the brakes themaximum brake cylin- I 'der pressure isobtainable.

Should the load on the vehicle be reduced when the door 79'is open, thecontrol-valve device will operate to reducethepressure of fluid in theadjusting piston 'chamber72 and the pressure of the spring 13 willmovethe piston 38 upwardly until the pressureon both sides thereof aresubstantially equal when it will come to a stop. As the piston thusmoves upwardly, the pressurewof the spring 19 of the brake cylinderpressure limiting valve device, through the medium of the plunger 20,bolt 21, arm 23 and shaft 24:, causes the arm 41 to remain inengagmentwith the roller 40 so that when the piston 38 comes to a stop theadjustment of'the spring 19 will cease. Now, when the door is closed thepawl 28 will be operated into locking engagement with. the arm 26 andthus maintain the pressure limiting .valve device adjusted. I I

. In the presentembodimentot the-invention, the upper sur'lface'of thearm .41, which is adapted to beieng'aged' by the roller of the adjustingpiston device 4, is curved up-y wardly so that when the arm isoperatedby the piston device,*the adjustment of the pres, sure ofthespring 19 of the pressure limiting valvelc evice 3 will, at all. times,be such diet the maximum pressure obtainable'in thebralre cylinder willbe directlyproportional to the tie braking power,"ofa door for thevehicle,

In Fig.- '2 a modification of the invention is illustrated which diliersfrom. the Zappa- V ratus illustrated in Fig.- 1, in that, the net valvedevice9 and the. several elements, of. the electric'circuit associatedtherewith and the vehicle door-79, and the reservoir are all omitted.and fluid underpressure, for

controlling the operation of the apparatus,

is supplied throughia door-opening pipe 86 leading to the door opening'side of a door engine 87 and alsoto the passage and pipe 70. Fluid underpressure, when supplied" to the door-opening pipe 86, flows to the dooropening side of. the door engine, causing said en ine to operate .to.open-the door. and also flows through the passage 70.1t0 the pawloperating piston chamber 71, the adjusting piston chamber 72 and'control diaphragm.

chamber 54, and with these 1 chambers thus 1- v supplied with fluidunder pressure, the ope; ations of this apparatu'sgwillbesubstantiallythe same as those described in connection with'the apparatus shown in-Fig. 1.

While two illustrative embodiments of the nvention have bQQllClGSCIlbGClin deta 1l,-1t

is not my ,intention'to limit its scope to these embodiments orotherwise thani'by the terms of the appended claims. r

Having now described my inventiomwhat I claim as new and desire tosecure. by Letters Patent, is z 1. In a variable loadbrake apparatus fora vehicle, the combination with means adjustable by fluid under pressurefor varying the braking power, of a door for the vehicle,

and means. operative upon 'the-opening of sand door-and according to theload on the:

vehicle for varying the pressure of fluid on said adjustable means.

2. In a variable load brake apparatus for a vehicle, the combinationwith means adjustable by fluid: under pressure for varying and meansoperative according to the load on the vehicle when the door is open forvarying the pressure of fluid on said ad .justable means.

3. In a variable load brakeapparatus for a vehicle, the combination withmeansaadjustable by fluid ,Lmder pressure for varying the ing- 01braking power, o f a door .for the..vehicle','-- andmeansoperativeac'cording 170213118 load onthe vehicle'when the door is openfor vary!v 7 ing the pressure of fluid=on said. adjustable I means andoperative upon the closing of said V '70 I .ooor for ca uslng ,said.mechanism. to be 'ilOCkQCl in; its adjusted position. 4. In a variableload brake apparatus for a Vehicle,the combination with-means justableby. fluid under pressure *forxvarying V i the braking power, .ofa door.for thevehicle, 'means. operatlveaccordmg to. the load on thevehlclewhen the door 1s open'for varying the pressure of fluid on saidadjustable means, :and means operative upon the 1 clos-" I '3 said doorfor maintainingsaid' ad-f justable means'in adjusted position.

5. In a variableload brake'apparatus for? avehicle, the combination withmechanism adjustablev by fluid under pressure for vary?- ing the brakingpower, of. addor. for the ve hiele, means operativeacGording 'to theload on the' vehicl'e" when the do'orI-wis openifon V varying thepressure of .fluid on said adjust able means, and means operative uponthe closing-of said-door for locking said meche anisminadjusted positionandoperative ing said'mechani'sm; 1 I 6; Ina variable load brakeapparatus for a vehicle, the combination with mechanism upon theopening'of said do or'for unlock? adjustableby fluid under pressure :forvarying :the-brakingip'ower, of la doo'r-for the vehiele, meansoperative'upon theopeningjof i sa d. door for supplyingfluid underipressure- .to sald mechanism, andmeans 'operatlvei.

[cording to-the load on the vehicle fo'r vary ing th'e pressure fluid'lnsa d mechanism. 1

7. In a variable load brake apparatus for a vehicle, the combinationwith mechanism adjustablefbyxfluid under pressure fOIfi'VillY- I ing thebraking-power, of adoor forTthe ve vhiele, means operative upon theopenin'g of said door for supplying fluid under presr I sure to saidmechanism, and .operativeupo'n the closing of said door forreleasingfluid under pressure from said; mechanism, and L4 adjustable by fluidunder'pressure for varying the braking power,'of a door for theveh1cle,- electro-re sponslve means operative upon the: opening of saiddoor for. supplying fluid under pressure to said mechanism, and meansoperative according to'the load 1 on the vehiclefor varying the pressureof fluid :in said mechanis 1 -1:;

9,111 a variable loadbrake apparatus for v a vehicle, the combinationwith mechanism means operativewhen the door is open'andi the-load on thevehicle reduced-for releasing v fluid under pressure from saidmechanism. i1 8. Ina variable'load' brakeapparatusfor' I a vehicle, thecombination with mechanism adjustable by fluid under pressure'for varyiing the braking power, ota door for thevehiele, means operative upon-theopening of;

said: door for! supplying fluidtund'er pressure" to ;S2L1Cl .mechamsm;and :pressure sensitive;

mean-s operative for controlling the-..:pressure:

of fluid in; said mechanism accordingto the;

load onthevehicle.

10. In a variableloadbrakefapparatus for a Vehicle, thecombinationwithemechanism adjustable by fluid under pressure f for;varying the braking, power of electroi-responsive valve means operative.toasupply fluid; under,

pressure to, said mechanism, and. a valve device. operative to controlvthe pressure I of fluid 1n sald. mechanismnaccording'to the load on thevehicle.

a vehicle, the combination; with; ,m'echanismj adjustable byv fluid;under pressuretfor vary ing-the sbrakingpowen, of. lectro responsive'mea-nsi :operative 'to supphyi fluid underpres sure to said mechanism,and; a .valve device I operative to V reduceithe .pressure :of fluid insa1d: mechanismuwhen athexload; on the ve-' j hicler is reduced vandtocause" the; pressure;

offluidin said mechanismiitoi be increased. When theload-onthewvehicletis increased.

12, In a variable z-lofad brake apparatus; for a vehicle, thecombination with: :Inechanisrn: adjustable by: fluid under jpressurezforv vary! ingthe' braking power, of electrosrespo nsive 1neansoperative to; supply: fluid under pressureto said, mechanism;.andiavalvedevice operativeto causethe pressureof fiLllCllIlSELld mechanism tobefiincreased and" decreased as the load on the car i'sfincreasedsanddecreased! 13.; In a variable load brake apparatus lfor a vehicle; thecombination Jvi-thia variable load mechanism: adapted: to; be operated;by 1 fluid under'pressure,of a doorzforthe vehicle,

inder,v 0f= adjustablei valve means fork con- 1 trollingthe supplyofaluidnunden pressure to the brake ;cylin'der;-:a mova blei'. abutmentfore'adj ustin'gjsaid'valve'means, lever opers ativeto controlthe-zoperation we said: abut-I ment-,.=a piston subj ectto the pressureof fluid for aoperatingsaid' lever, a door: for :the live hicle, means:operative upon the opening of said door for--.subjectingasaid"pistonrtothe pressure" ofifluid iand :meansoperated :ac

cording-.totthe load on the-vehicle for controlling the pressure offluid: on said piston;

15.. Inla variable load brake: apparatus: for a vehicle, the combinationwith a brake cyl inder, of adjustable valve means: for=controllinga-thei-supply jot fluid under pressure to' thebrakeicylinderya :piston ldevice subject to -fluid:- underpressurenfori; adjusting said valve means, a valve'devicei operative to?sup;

11. In a variable load brakerapparatusrfor ply: fluid un'd'erQpressure.to: said piston ;de-, 9 hvice, and valveimeans operative accordingitov.the'load on i' the vehicle for controlling the pressure of .fluidiinsaid piston device.v

16;: "In a variable load brakeapparatus .for 1 Ti) Li I a vehicle,the-combination with a brake cylinder,of adjustablevalve meansforcontrol-x ling the supply. offluid u-nder pressure. :to e thebrakeqcylinder, alpi'stonqdevice subject to 1 fluid. under. pressure.Ifor adjusting said valve means, a valve device operative to supp-splyfluidunder pressure to saidpiston de-i .vice, and valve meansoperative upon-move- ,.pressure. of fluid in said- .v'al've' device; 1 Y

a vehicle, the combination with abrakecyl- .inder, of ad ustableivalvemeansvformcon .:,trolling the supply of fluid under pressure tothe'brake cylinder, .apistondevice sub-1' 'je'ct to jfluidunder:prejssure for adjusting said "valve means, a valvedevice operative tosupply fluid under pressure tosaid piston device, and valve meansinterposed between 'the: body and truck of the vehicle operativeaccording to the load on thevehicl'eibody for controlling the pressureof'fluid'in said piston device.

, -ment :of the body of theivehicle relativegto a truck of the vehiclefor controlling" the 17; in a variable load brake apparatustor 1 18;Inca variable load brakeapparatus for a vehicle,-'theCOlIlblIliLillQIl'Wlth a brake cylinder, of'a'valve device adjustableaccordmg I to thes'load'on the vehicle for limitingthe supply of fluidunderpressure to thebrake ..:cylinder, levermeans operative toa'djustsaid valve device, pawlroperative into and out of locking engagementwith said lever means, pressure sensitive means for operatlng-saidpaWl,-p1st0n means for controlling the op.-

veration of said lever means, valve means. for

supplying fluid under pressure to saidpressure-sensltlve means foroperating said pawl out of locking engagement withsaid levermean'sandrfor' supplying fluid under pressure-to saidzpiston device, andmeans opera- ,tiv'e according to the load on the. vehicle forcontrolling the pressure of fluid in the piston :device and thereby theoperation of said piston'device. i

a vehicle-",- the combination with a brake 'cyl- 1 9. In a variableload'brakei' apparatus for inder, of a valve device adjustable accordingto the load on the'vehicle for limiting the 1* supply of fluid underpressure tothe' brake cylinder, lever meansoperative'to ad ust saidval-vez'device, saidmeans comprislng az lever having a curved surface,and :fluid pressure -controlledmeans for controlling theoperation ofsaid lever means, said fluid pressure controlled-v:means cooperatingwith said curved surface f rJadjuSting said valve de'- vice directlyproportional totheimovement 1 of saidhfluid pressure controlled means. vI

20.: In a 1 variable l'oad :br'ak'e' "apparatus;

' for. a. vehicle, th'ecombination :With' a brake 1 cylinder, of a valvedevice adjustable according to the load on the vehicle for limiting thesupply of fluid under. pressure to the brake cylinder,-lever meansoperative to ad'- just said valve device,-sai'd. means comprising. alever having a curved'portion, and fluid pressure controlled meansCOOPGIZLtin'g-With. the curved portionof said lever to adjust said valvedevice directly proportional to the movement of the fluid pressurecontrolled meansr I a 21. In a variable load brake apparatus for avehicle, the combination Witha brake cylinder, of a valve deviceadjustable according to the load on the vehicle for limiting .the. Vsupply of fluid under pressure to the brake cylinder, lever meansoperative to ust said valve device, saidmeans comprising a lever movablein the arc of a circle, pressure sensi-- tive meansioroperatingsaid'lever and mov-i able tangentially-to the path of travel ofsaid lever, and'means on. said .levrwvith which said pressure sensitivemeans cooper ates to cause said lever to operateto adjust said valvedevice directly proportional to the movement of said pressure sensitivemeans. 1 v

22. In avariable load brake apparatusfor a vehicle, the combination\vith a brake cyl-. inder, of a valve device adjustable according-to theload on the vehicle for-limiting the supply of fluid under pressureto-the brake cylinder, lever 1neans operative to adjust saidvalvedevice, said means comprising; a lever movable in the are ofa'circle about a fixed pointl-and having acurved end portion, andpressure sensitive means for con trolling the operation of said levermovable tangentially t the path of travel of the lever and cooperatingwith the curved end portion thereof for adjusting said valve devicedirectly proportional to theinovement of said pressure sensitive means.

23. In a. variable load brake apparatus for a vehicle, the combinationwith means adj ustable according to the load on the vehicle 'iorregulatingthe braking power, of a lock- 4 ing device for locking saidmeans inan adjusted position and released .by'fluid under pressure, adoor for the vehicle, and .means operative upon the opening of said doorfor supplying fluid under ing device.

24. In a variable load brake apparatus for pressure to said lock- .avehicle, the combination with means adjustable according to the load onthe vehicle for re ulatin the brakin oWer of a locka p ing device iorlocking said means in an aojusted position and-released by fluid underpressure, a door for the vehicle, means operative upon the opening ofsaid door for supplying fluid under pressure to said locking device andoperative upon the closing of said door to releasefluid underpressurefromsaid locking device, and means for returning said vice. I

29. In avariable load brake apparatus,the

locking device "to locking"positioniivhen'fluid under pressure isreleased therefrom. 25. Ina variable load brakezapparatus' tor avehicle, the COHlblIlZtijlOH with means adr ,justableaccording to theload on the, vehicle for regulating the braking power, of a loclrdevicefor locking said means in an ad'- justed position and released by fluidunder v ing device for locking'saidimeans in an adusted positionandreleased-gby fluidunderpressure,-aldoor for the vehicle, and. meanscontrolled'by the operation of-said door for supplying and releasingfluid under pressure to and from said locking device.

27. In a variable load brake'apparatus, the t combination with a brakecylinderpofanad; justable valve device operative- .to l'imit thepressure of fluid supplied .to'thebrakecylinder, lever means operativeto adjust said valve device, a fluidpressure controlled-"deviceforcontrolling the .operation of said lever means;

ajloclzing device engaging said lever means for locking said valvedevice in adj usted'posi- 13 tion, piston device operative by. fluidunder pressureior releasing said lockmg device,

andmeans for supplying fluid under pressure pressure controlleddevicela'nd to said fluid piston devlcei 28;;Ina variable load brakeapparatus,the. combinatlon With a brake cylinder, of an ad- Joejustable'valve device operative to limit the 1 pressure of fluidsuppliedt'othe brake cylin--.'

der, lever means operative toadju-st said valve-device, afluid pressurecontrolled de-j vice r01 controlling the operation of said lever means,a lockingdevicezengaging said lever means for locking said valve devicein adjusted position, a piston device operative lie by fluid underpressure for releasingsaid l cking device, and-operative;to returnflsaidlocking deviceinto locking engagement with said leverrmeans'upon therelease of fluid under pressure fromithe piston device,means forsupplying and releasing fluid under pressure. to and from said fluidpressure controlled device-and piston fdevice, and means for retardingthe release of fluid under pressure from said fluid pressurecontrolleddecombination With abralre cylinder,'of an adjustable valve; deviceoperative to limit the pressure of fluid supplied to the brake cylinder,lever means operative to adjustsaid valve device, afluid pressurecontrolled'device ior controlling the operation-of said lever'means,.Jalockin'g device engaging said levermeans for locking said -valve devicein adjusted position, a piston device operative by fluid unoerpressurefor releasing rsaidlocking device, and operative to'return said lockingdevice into locking engagement with said lever means upon the release offluid under pressure from the piston device, means for supplying andreleasing fluidunder pressure to and from said fluid pressure controlleddevice and piston device, and means whereby the flow offluid releasedfrom said fluid pressure controlled device will be at a slower rate thanthat from said piston device. Y

30. In a variable loadbrake apparatus, the combination with a brakecylinder, or an adjustable valve device operative to limit the pressureof fluid supplied-to the brake cylinder, lever means operative to adjustsaid valve device, a fluid pressure controlled de vice for controllingthe operation of'said lever means, a locking device engaging said levermeans forlocking said valve device in adjusted position, a'piston deviceoperative by fluid under pressure for releasing said locking device,means for supplyiiig a predetermined amount of fluid under pressure tosaid piston device and fluid pressure controlled. device at anunrestricted rate, the

pressure of fluid, thus supplied being sufflcient to operate saidpistondevice only, and

1 means for increasing the pressure of fluid in said fluid pressurecontrolled device at a stricted rate after theunrestrictediflow of fluidunder pressure has ceased.

31. In a variable load brake apparatus,

. the combination with a brake cylinder, of an adjustable valve deviceoperative to limit the pressure of fluid supplied to the brake cylinder,lever meansoperative to adjust said valve device, a fluid pressurecontrolled device for controlling the operation of said lever means, alocking deviceengaging said lever means for locking said valve device inadjusted position, a piston -.device operative by fluid under pressurefor releasing said locking device, two connected reservoirs normallycharged with fluid under pressure, means operative to establishcommunication through which fluid under pressure is supplied from bothof said reservoirs to said pistondevice and fluid pressure controlleddevice, the flow of fluid from one of said reservoirs being at anunrestricted rate-and of a pressure sufiicientto operate said pistondevice only, and means for restricting the flow of fluid under. pressurefrom the reservoirs. r

82. Ina variable load brake apparatus, the combination with a brakecylinder, of an adj ustablevalve device operative to limit the pressureof fluid supplied to the:brake cyl inder, lever means operative toadjust saidvalve device, a fluid pressure controlled device-forcontrolling the operation of said lever means, a locking device engagingsaid other of said device, the flow of fluid from one ofsaid reservoirsbeing at an unrestricted rate and of a pressure sufficient to operatesaid piston device only,i.and means for retarding the build up ofpressure in said fluid pressure controlled device from :the. other ofsaid I reservoirs. I i

'33. In a variableload brake apparatus,

the combination with a brake cylinder, of an adjustable valvedeviceoperative to limit the pressure of fluid supplied to thevbrakecylinder, lever means operative to adjust said valve device, a fluidpressure controlled device' for controlling the operation of said levermeans, a. locking device engaging said lever means forlocking said valvedevice in adjusted position, a piston device operative by fluid underpressure for releasing said locking device, two: connected reservoirsnormally charged with fluid under pressure,

means operative to establish communication through which fluid underpressure is supplied ,froinboth ofsaid reservoirs to said pistondevice.v and fluid pressure controlled device, the ,flow of fluid fromone of said reservoirs being at an unrestricted rate and of pressuresufficient to operate said piston device only, and means tor restrictingthe flow of-fluid under pressure from the other of said reservoirs todelay the operation of said fluid pressure controlled device.

In" testimony whereof I have hereunto se my hand, this 9th day ofOctober,1929.

v UNCAS A. WHITAKER.

i y A 4 lever means for locking said valve device in

